U.S. Pat. No. 4,400,340 and U.S. Pat. No. 4,426,502 disclose the production of a molded article by injecting two kinds of reactive solutions, one of which comprises a norbornene-type monomer such as dicyclopentadiene and the catalyst component of a methathesis polymerization catalyst system and the other comprises a norbornene type monomer and the activator component of the catalyst system under a impingement mixing into a mold in which said liquid mixture is metathesis polymerized in bulk (called "RIM process" hereinafter). RIM process is a low pressure one-step or one-shot injection process and the liquid mixture injected into the mold polymerizes rapidly to form a molded article. Thus, one can easily and cheaply produced large-sized molded articles from norbornene-type monomers such as dicyclopentadiene by RIM process.
The molded articles produced from norbornene-type monomers are, however, usually from light to dark yellow when not colored or not surface-coated. Further, the molded articles produced from norbornene-type monomers have many unsaturated bonds which are susceptible to oxidation and these articles have poor light resistant and anti-oxidant properties. In usual use, therefore, these molded articles must be colored by mixing pigments in the starting composition or coated to provide the molded articles with a beautiful finish and stability.
U.S. Pat. No. 4,598,102 teaches the addition of reinforcing agents or fillers such as glass, wolastonite, mica, carbon black, talc and calcium carbonate into the metathesis polymerizable composition of cyclic olefin monomers. However, U.S. Pat. No. 4,598,102 does not speicfically disclose the kind of carbon black nor does it teach mixing the carbon black specifically with the catalyst component or the activator component of the metathesis polymerization catalyst system.
U.S. Pat. No. 4,080,491 teaches the addition of a coloring agent into a metathesis polymerizable norbornene-type monomers, but does not specifically disclose any kind of coloring agent.
On the other hand, the prior art teaches that the activator component of a metathesis polymerization catalyst system (such as aluminum trialkyls or alkylaluminum halides) is more reactive and unstable than the catalyst component of the metathesis polymerizatrion catalyst system (such as tungsten or molybdenum salts). Thus additives such as fillers and pigments have been added in the prior art into the monomer solution containing the catalyst componenet rather than into the monomer solution containing the activator component.
As a result of our stydy of the coloring of the metathesis polymerized molded articles comprising cycloolefin polymer, we have found surprisingly that, among many pigments, particular pigments based on carbon black prepared by an incomplete combustion process, titanium oxides, iron oxides and cobalt oxides can be added to the reactive solutiohns to form reactive solutions which are storable for along period of time without loss of activity. This effect is brought out only when the pigments are dispersed in the reactive solution containing the activator component (Solution B) instead of being dispersed in the solution containing the main catalyst component (Solution A) which is usually understood to be less reactive than the former. Actually, the interaction between the catalyst component and the above-mentioned pigments is not so vigorous, but it is long-lasting. That is, Solution A is gradually deactivated under the presence of the above-mentioned pigments, and when once deactivated, an additional charge of the catalyst component cannot restore the activities enough. On the other hand, the interaction between the activator component and the mentioned pigments, if any, seems to be very rapid, and soon stops. An additional charge of activator to compensate for the consumed portion can bring back the activities of the activtor to substantially the initial activity and results in the composition having very stable activities when stored. This is a very unexpected finding and advantageously applicable to the manufacture of colored molded articles from the mentioned reactive solutions. But these phenomena have not been observed with any metal oxides. For instance, antimony trioxide has been shown to react not only with the catalyst component, but also with the activator componenet resulting in a gradual deactivation of Solution B when dispersed in Solution B. Fortunately, the recited pigments can be used to provide a variety of colors, for example, from black to white, and from red to violet by modifying the structures of the pigments, adding other small components or mixing of some of them as mentioned later in detail.
We have further found that the colored molded articles formed from the reactive solutions containing the pigments in Solution B have a clearer color than those formed from the reactive solutions containing the pigments in solution A, especially when light-colored pigments are used. The Solution A is usually dark-colored due to the catalyst component. Such dark-colored component may remain absorbed on the surface of the pigment particles even after the completion of the polymerization and affect the color of the pigmented articles, though most of the dark-colored component will be decolored during the polymerization.
Thus, we have found that carbon black from incomplete combustion, titanium oxides, iron oxides, and cobalt oxides, when dispersed in the reactive solution containing the activator component, can provide beautifully colored molded articles without affecting the reactivities of the solutions after storage.
Therefore, it is an object of the present invention to provide a process for producing colored molded articles of metathesis polymerized cross-linked polymers having a beautiful finish and anti-oxidant and light resistant properties.
A further object of the present invention is to provide a multi-part metathesis polymerizable composition useful for the production of the colored articles.